放疗参考点在平板床和非平板床CT片中变化的研究

Study on Difference of Radiotherapy Referred Point Between Round Couch and Flat Couch CT Scan

目的 :比较体内某参考点在平板床和非平板床CT片上的变化情况。方法 :选择 36例同时摄平板及非平板床CT片的成人胸部肿瘤患者 ,测量两种条件下CT片上前后径、体内参考点到前、后表面正中的距离。结果 :两种条件下 (平板床与非平板床 )CT片上前后径、前径及后径差值均数分别为 :(0 82± 0 5 8)cm ,95 %CI[0 84 36 ,0 2 80 8];(0 5 6± 0 4 3)cm ,95 %CI[0 5 487,0 12 4 4];(0 5 0± 0 4 1)cm ,95 %CI[0 4 2 30 ,0 0 0 2 0 ]。 3组数据经自身配对t检验差异均有显著意义 ,t值分别为 4 0 5 6、3 196、2 2 35 ,P值分别为 0 0 0 0 3、0 0 0 31、0 0 316。结论 :用CT片制定放射治疗计划时应充分考虑平板床与非平板床的差异。

Objective To study the difference of referred point between round couch and flat couch CT scan.Methods Thirty six adult patients with chest tumor who had diagnostic and radiotherapy treatment planning CT scan at the same time were selected,and the body thickness,anterior and posterior depths of them were measured in two conditions,round couch and flat couch.Results The average differences between two CT scans were (0 82±0 58)cm,95%CI[0 843 6,0 280 8];(0 56±0 43)cm,95%CI[0 548 7,0 124 4];(0 50±0 41)cm,95%CI[0 423 0,0 002 0],respectively.All the differences were significant statistically by Paired Samples T test ( t =4 056, P =0 000 3; t =3 196, P =0 003 1; t =2 235, P =0 031 6).Conclusions The difference between round couch and flat couch should be concerned fully when a CT scan is being obtained for radiotherapy treatment planning.